//#pragma comment(linker,"/STACK:16777216") /*16Mb*/
//#pragma comment(linker,"/STACK:33554432") /*32Mb*/
#define _CRT_SECURE_NO_DEPRECATE
#include<sstream>
#include<iostream>
#include<numeric>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<memory>
#include<string>
#include<vector>
#include<cctype>
#include<list>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<algorithm>
using namespace std;

typedef unsigned long long      ui64;
typedef long long               i64;
typedef	vector<int>             VI;
typedef	vector<bool>            VB;
typedef	vector<VI>              VVI;
typedef	vector<string>          VS;
typedef	pair<int,int>           PII;
typedef map<string,int>         MSI;
typedef set<int>                SI;
typedef set<string>             SS;
typedef map<int,int>            MII;
typedef	pair<double,double>     PDD;

#define PB                      push_back
#define MP                      make_pair
#define X                       first
#define Y                       second
#define FOR(i, a, b)            for(int i = (a); i < (b); ++i)
#define RFOR(i, a, b)           for(int i = (a) - 1; i >= (b); --i)
#define CLEAR(a, b)             memset(a, b, sizeof(a))
#define SZ(a)                   int((a).size())
#define ALL(a)                  (a).begin(), (a).end()
#define RALL(a)                 (a).rbegin(), (a).rend()
#define INF                     (2000000000)

#ifdef _DEBUG
#define eprintf(...) fprintf (stderr, __VA_ARGS__)
#else
#define eprintf(...) assert (true)
#endif

int main()
{
	i64 n;
	scanf("%lld",&n);
	vector<i64> a(n);
	FOR(i,0,n)
		scanf("%lld",&a[i]);
		//a[i] = 10000;
	long double xi_2 = 0;
	long double xi = 0;
	long double xiyi = 0;
	long double yi = 0;
	for(i64 i=0;i<n;i++) {
		xi_2 += i*i;
		xiyi += a[i]*i;
		yi += a[i];
		xi += i;
	}
	
	long double z = n*xi_2 - xi*xi;
	long double dx = yi*xi_2;
	long double A = yi*xi_2 - xiyi*xi;
	long double B = n*xiyi - yi*xi;
	long double AA = A;
	long double BB = B;
	long double zz = z;
	AA = AA/zz;
	BB = BB/zz;
	const double eps = 1e-14;
	AA += eps;
	BB += eps;
	
	printf("%.9lf %.9lf\n",AA,BB);
    return 0;
}